Firstly, I don’t believe in balance at all. This is subjective, there will always be problems, there will always be discontent. I believe in new content, it is material and provides an incentive to continue an already long game.
Secondly, it was possible to divide the balance for 1 versus 1 and for team games, their gameplay is different and they must be balanced in different ways.

Let's take a simple example to show to you that you really don't know what you are asking:
Lets assume grens and cons are perfectly balanced in 1v1. What change do they need to make to balance them in 2v2? My point is if the factions are perfectly balanced in 1v1 why they need to be balanced in 2v2? How are they umbalanced?

You and everyone else can easily look up these numbers. Go to this site and check the amount of players for each mode and faction. For this, scroll to the bottom, there you can see a "jump to page.." field. Enter a number like 999 and you will get sent to the last site, showing you the number of players.

In WM 2v2 ladder for example 4199 is the number of unique players that play 2v2? You mean that there are out there 4199-2777=1422 players who play more 2v2 or even only 2v2 ? That's the whole brit ladder players.